Abstract
Background
Epidemiological studies have shown diabetes associated with increased risk of colorectal cancer. This study investigates the impact of a pre-cancer diabetes-related hospitalization record on colorectal cancer survival.
Methods
A retrospective cohort of 13190 colorectal cancer patients recorded on the South Australian Cancer Registry in 2003-2013 were examined. Diabetes-related hospitalization histories were obtained using linked inpatient data. Colorectal cancer deaths were available for 2003-2013. The association of survival from colorectal cancer with diabetes-related hospitalization history was assessed using competing risk analysis, adjusting for sociodemographic factors and cancer stage at diagnosis.
Results
2765 patients with colorectal cancer (26.5%) had a history of hospital admission for diabetic complications, the most common being multiple complications (32%), followed by kidney and eye complications. The 5- and 10-year cancer survival probabilities were 63% and 56% in those with a diabetes complication history, significantly lower than 66% and 60% for patients without these complications (adjusted sub hazard ratio 1.11, 95% CI 1.02-1.20). Risk of colorectal cancer death was lower when theses diabetes-related hospitalizations were earlier than the year of cancer diagnosis - i.e., adjusted SHR 0.80, 95% CI 0.66-0.97 for 3-5 and 0.76, 95% CI 0.59-0.98 for 6+ years before the cancer diagnosis compared with same-year hospitalizations.
Conclusions
Colorectal cancer patients with a history of diabetes-related hospitalization have poorer survival, particularly if these hospitalizations were in the same year as the cancer diagnosis.
Key messages
Poorly controlled diabetes histories predict increased risk of colorectal cancer mortality.
The impact on colorectal cancer survival of cases registered by 'death certificate only': implications for national survival rates
